Last minute inquiry... asking for a discount...sounds not so desirable to me.
In any case, you did all you possibly could to enable this booking. Who knows what exactly she means when she simply says that she has actually submitted verification credentials to Airbnb.
At this point, if you are still wanting to get this rental, you could go into your listing, check on reservation requirements, apparently you have "require guests to go through verification" enabled - so disable that, then send her a new offer, or have her request it again. Lots of tedious steps... Good luck!